“Abstract
Background context
Several therapies have been used in the treatment of chronic low back pain (LBP), including various exercise strategies and spinal manipulative therapy (SMT). A common belief is that spinal motion changes in particular ways in direct response to specific interventions, such as exercise or spinal manipulation.

Purpose
The purpose of this study was to assess changes in lumbar region motion for more than 12 weeks by evaluating four motion parameters in the sagittal plane and two in the horizontal plane in LBP patients treated with either exercise therapy or spinal manipulation.

Study design/setting
Secondary analysis of a subset of participants from a randomized clinical trial.

Patient sample
One hundred ninety-nine study participants with LBP of more than 6 weeks’ duration who had spinal motion measures obtained before and after the period of intervention.

Methods
Trained therapists collected regional lumbar spinal motion data at baseline and 12 weeks of follow-up. The lumbar region spinal motion data were analyzed as a total cohort and relative to treatment modality (high dose, supervised low-tech trunk exercise, SMT, and a short course of home exercise and self-care advice). The study was supported by grants from Health Resources and Services Administration, Danish Agency for Science Technology and Innovation, Danish Chiropractors Research Foundation, and the University of Southern Denmark. No conflicts of interest reported.

Results
For the cohort as a whole, lumbar region motion parameters were altered over the 12-week period, except for the jerk index parameter. The group receiving spinal manipulation changed significantly in all, and the exercise groups in half, the motion parameters included in the analysis.

The spinal manipulation group changed to a smoother motion pattern (reduced jerk index), whereas the exercise groups did not. “